Proposal of self-excited wound-field magnetic-modulated dual-axis motor for hybrid electric vehicle applications

This study proposes a permanent-magnet (PM)-free magnetic-modulated motor where the magnetic flux variation in a differential frequency between the armature fundamental rotating magnetic field frequency and the rotor rotation speed frequency is effectively utilised for the field magnetisation instead of PMs. The operation principle of the self-excitation with a diode rectifier circuit on the rotor is discussed. Magnetic circuit design and structural design of downsized prototype machine are performed for the purpose of experimental verifications of self-excitation. In addition, the preliminary experimental test results are demonstrated with prototype machine. Consequently, it is confirmed that the proposed PM-free magnetic-modulated motor can automatically obtain the field magnetisation power by utilising differential frequency which is inevitably generated by magnetic-modulation technique.